The Hemoglobin A1c (HbA1c) Test measures your average blood sugar levels over the past 3 months. This blood test helps determine whether you’re at risk for prediabetes or diabetes. If you have diabetes, HbA1c testing can help you and your healthcare provider know how well you're managing your blood sugar levels over time. An elevated HbA1c level means that your blood sugar levels have been high over the past 3 months. The HbA1c Test reports the percentage of hemoglobin in your blood that is coated with sugar. A higher percentage of HbA1c indicates higher blood sugar levels.